A man has two children. One of them is a boy.

[Diablo]

Did not think it was a trick question..but the fact is that if you have two children and you state "ONE of them is a boy"...you are saying also that the other one isn`t.

Sorry...but do you agree....others it seems don`t..

 

[Diablo]

Blimey keep up. We've been there at post #15

Sorry but do you agree...most don`t

 

[Triggaaar]

Yes

Any chance you'll put some money on it

 

[Arthritic Toe]

Sorry but do you agree...most don`t

Well I started trying to defend that line of argument for argument sake, but in the end I conceded the key point, which is that "One of them is a boy" does not really imply anything about the other one. It could be taken to mean "Only one of them is a boy" or "At least one of them is a boy". Without the words "only" or "at least", it is ambiguous. However I reckon that common accepted usage puts it pretty firmly in the "at least" camp. Hence, I decided I was trying to defend an untenable position and abandoned that line of argument.

 

[hans kraay fan club]

You think the chance of the other being a boy is 1 in 3? It's not, it's 1 in 2 (50%).

If you word it how you have then of course.

I'll have to leave it there and do a TINY bit of work.

 

[Moshe Gariani]

This is a little difficult to word, but basically:

"What is the probability of two children both being male, given the proviso that at least one definitely is?"

You have four possibilities (b/g, b/b, g/g, g/b), but the proviso allows you to rule out one of them.

If you think of it as heads and tails instead of boy girl, its perhaps easier to look at the raw probabilities / possibilities.

Hans, with all due respect (i.e. none at all..!), this is nonsense. How on earth is b/g a different outcome to g/b when you are not worried about the order...?

 

[GingerBeerMan]

Any chance you'll put some money on it

Sorry to ruin your fun, but I think the actual answer is 'no one knows'. It's an ambiguous maths problem which different people will give different answers to depending how you interpret it. You're not wrong, neither is HKFC. There's lots written on the internet about it and it's an interesting case to read if you like statistics. (Hope this hasn't killed the mood)

 

[Diablo]

Well I started trying to defend that line of argument for argument sake, but in the end I conceded the key point, which is that "One of them is a boy" does not really imply anything about the other one. It could be taken to mean "Only one of them is a boy" or "At least one of them is a boy". Without the words "only" or "at least", it is ambiguous. However I reckon that common accepted usage puts it pretty firmly in the "at least" camp. Hence, I decided I was trying to defend an untenable position and abandoned that line of argument.

"A man has two children. One of them is a boy". If this statement is true..Other Child is not a boy....FACT.....Of the two children that this man has "One is a boy" therefore the other one is not a boy or original statement is false.

 

[Triggaaar]

If you word it how you have then of course.

You can word it however you like. I was just trying to word it in a clear way so we all understand what's being debated.

Your wording was:

"What is the probability of two children both being male, given the proviso that at least one definitely is?"

You have four possibilities (b/g, b/b, g/g, g/b), but the proviso allows you to rule out one of them.

If you think of it as heads and tails instead of boy girl, its perhaps easier to look at the raw probabilities / possibilities.

That's the same thing. It's 50%. You've stated you disagree. I can prove that you're wrong, but first I want to see if I can hustle some money out of you You did study statistics at uni remember, so think of it as an opportunity to take some money off me and shut me up. The whole of NSC will be forever in your debt. I'll consider bets from 1 beer to £1000.

I'll have to leave it there and do a TINY bit of work.

Do your work, then face the music. Dancing is optional.

 

[Arthritic Toe]

Sorry to ruin your fun, but I think the actual answer is 'no one knows'. It's an ambiguous maths problem which different people will give different answers to depending how you interpret it. You're not wrong, neither is HKFC. There's lots written on the internet about it and it's an interesting case to read if you like statistics. (Hope this hasn't killed the mood)

Have you considered a job with the UN?

 

[Diablo]

Sorry to ruin your fun, but I think the actual answer is 'no one knows'. It's an ambiguous maths problem which different people will give different answers to depending how you interpret it. You're not wrong, neither is HKFC. There's lots written on the internet about it and it's an interesting case to read if you like statistics. (Hope this hasn't killed the mood)

"A man has two children. One of them is a boy." ....what is ambiguous in the statement. it is either true or not...if true the other child can not be a boy...

 

[Triggaaar]

Sorry to ruin your fun, but I think the actual answer is 'no one knows'. It's an ambiguous maths problem which different people will give different answers to depending how you interpret it.

The OP is ambiguous and open to interpretation, but we are expanding on the original question such that it becomes one of statistics, that can be answered.

 

[Moshe Gariani]

"A man has two children. One of them is a boy". If this statement is true..Other Child is not a boy....FACT.....Of the two children that this man has "One is a boy" therfore the other one is not a boy or original statement is false.

Good work Diablo.

I have an image of you in a Roman amphitheatre holding court to a small group of disciples who follow the true answer while a little distance away a Michael Palin type figure (HKFC) sits on the stone steps espousing a one in three hypothesis ...

 

[Arthritic Toe]

"A man has two children. One of them is a boy". If this statement is true..Other Child is not a boy....FACT.....Of the two children that this man has "One is a boy" therefore the other one is not a boy or original statement is false.

Well thats what I was arguing earlier. But the statement "A man has two children. One of them is a boy" is ambigious, and your argument holds only if you take it to mean "only one". That's why i gave up on it.

 

[hans kraay fan club]

The OP is ambiguous and open to interpretation, but we are expanding on the original question such that it becomes one of statistics, that can be answered.

No, I'm with him. Its the ambiguity that we are at odds over rather than the probability.

 

[Official Old Man]

None.
Well not in my case, three Daughters, and I love them all (in a Dad / Daughter way please).

 

[AlbionPics&SouthCoastTwit]

No, I'm with him. Its the ambiguity that we are at odds over rather than the probability.

It depends on the ambiguity of the statement "I'm with him." But it probably means I agree with his statement. Although it could mean we are in a horse costume together and he is an ass.

 

[Triggaaar]

No, I'm with him. Its the ambiguity that we are at odds over rather than the probability.

Well we've certainly moved away from some of the ambiguity of the original question, but we may still have some issues with the question.

This is your reworded question: "What is the probability of two children both being male, given the proviso that at least one definitely is?" You also said to "think of it as heads and tails instead of boy girl".

In order to clarify any ambiguity, how did you find out that one is definitely a male? (or heads)

 

[Diablo]

Well thats what I was arguing earlier. But the statement "A man has two children. One of them is a boy" is ambigious, and your argument holds only if you take it to mean "only one". That's why i gave up on it.

"One out of two"...... "One Boy out of two Children is as clear factually as it can be.......

 

[Moshe Gariani]

Well we've certainly moved away from some of the ambiguity of the original question, but we may still have some issues with the question.

This is your reworded question: "What is the probability of two children both being male, given the proviso that at least one definitely is?" You also said to "think of it as heads and tails instead of boy girl".

In order to clarify any ambiguity, how did you find out that one is definitely a male? (or heads)

There is limited or no REAL ambiguity in the original question. He found out one is male because I clearly told him in the question. I don't see how this reworded question is different.